Drive mechanism with holder for material to be sewn and sewing machine with such a drive mechanism

ABSTRACT

A drive mechanism for a sewing machine, for example an embroidery unit ( 10 ), has a holder for material to be sewn, which is attached to an arm carriage ( 20 ) which is displaceable on an arm ( 19 ), wherein the arm for its part is displaceable on a support carriage ( 16 ) perpendicularly in respect to the arm carriage ( 20 ). The bulky size is disadvantageous in connection with known support-arm constructions. To avoid this it is proposed to design the arm to be pivotable around a joint ( 18 ) into a position of rest, in which the arm ( 19 ) and the support ( 14 ) extend essentially parallel with each other.

[0001] The invention relates to a drive mechanism with a holder for material to be sewn, for example an embroidery unit with an embroidery frame, which is attached to an arm carriage which is movable along a first track of an arm, wherein the arm is attached on a support carriage, which on a support for its part is movable along a second track extending perpendicularly to the first track in an operating position. Further, the invention relates to a sewing machine provided with such a drive mechanism.

[0002] The customary designs of such drive mechanisms, for example for embroidering units, such as disclosed in DE 295 14 286 U1, for example, normally provide rigid shafts, so that a requirement for a large space results. Considerable impediments and disadvantages regarding costs result, particularly in connection with packaging, transporting and storage of the embroidery units, which often are available as detachable accessories for sewing machines.

[0003] Therefore the object of the present invention lies in designing a drive mechanism with a holder for material to be sewn for a sewing machine in such a way, that in the unused state it can be stored and transported in a simpler and more cost-effective way.

[0004] In accordance with the invention, this object is attained in that the arm is pivotable around a joint from the operating position into a position of rest, in which the two tracks are essentially located parallel to each other. Because the arm can be swiveled away, a considerable space savings results in the position of rest, which permits smaller, and therefore more costefficient transport containers, for example for the embroidery units, which can be obtained as accessories for sewing machines.

[0005] In spite of transport containers which are reduced in size, it is possible here to increase the movement area by means of an increased length of the arm and therefore the capability of processing larger pieces of material to be sewn.

[0006] Respectively one stop suitably limits the pivot range of the arm in the position of rest and in the operating position. Wrong positions and possible damage by turning the arm too far are dependably prevented by means of this.

[0007] The arm preferably is arranged to be positively locked at least in its operating position. Interlocked securing or positive locking, respectively, assures that no displacement of the position of the arm can occur during the operation. In this connection a particularly preferred embodiment provides that the interlocking securing or latching elements can be disengaged against the force of a spring element. The automatic latching of the latching elements after reaching the operating position of the arm is achieved in this way, so that it is possible to almost completely prevent erroneous operations.

[0008] Besides separate securing elements, which can be provided for achieving the positive locking between the arm and the support and which are movable independently of the latter, it is provided in a further preferred embodiment of the invention that the interlocked latching elements are provided directly or indirectly on the arm and/or the support carriage. The disengagement movement of the arm then takes place by moving the entire arm in relation to the support against the force of the spring element. Here, a particularly practical embodiment provides that the arm can be axially displaced on its pivot shaft against the force of the spring element into a position, in which the positive locking is interrupted. With such a solution the user merely needs to grasp the arm and pull it slightly upward, after which it can be pivoted into the desired position.

[0009] The interlocking latching elements are preferably embodied in such a way that a first axial front face is provided on the arm, and a second axial front face around the pivot shaft on the support carriage, wherein the front faces have matching groove and projecting elements acting as latching elements, which can be disengaged by raising the arm.

[0010] It is easily possible with such a solution to provide an interlocking latching possibility both in the position of rest and in the operating position, wherein a secure seating in the pivot direction is assured by means of an appropriately large embodiment of the latching elements. A preferably conical design of the latching elements can make the interlock process easier. Moreover, the conicity, together with the spring element, results in a play-free securing, so that the holder for the material to be sewn can be positioned particularly precisely.

[0011] To prevent a collision of the mechanical parts with the shells in the course of raising the arm, the lifting track can be limited in the direction of the unlocked position by a stop, for example by the embodiment of divided pivot bearing bushings, whose fronts facing each other constitute the stop.

[0012] Especially an electric motor for each of the carriages is available and the motor of the arm carriage is preferably arranged in the arm, and the motor of the support carriage preferably in the support, wherein at least on of the motors in a further preferred embodiment acts via a toothed belt drive. However, it would also be conceivable in principle to arrange both drive motors in the support and to arrange a pulley of the toothed belt drive, for example, around the pivot shaft, wherein the change of the position of the arm carriage caused by the pivot movement can be accommodated without problems.

[0013] In a sewing machine with a drive mechanism according to the invention the support is preferably designed to be removable from the sewing machine housing or sewing machine body.

[0014] An exemplary embodiment of the invention will be discussed in greater detail in what follows, making reference to the attached drawings. Shown are in:

[0015]FIG. 1, a schematic plan view of an embroidery unit in the operational position,

[0016]FIG. 2, the embroidery unit in the folded position of rest or transport position, respectively,

[0017]FIG. 3, a cross section of the embroidery unit in FIG. 2 in the latched position of rest,

[0018]FIG. 4, an enlarged portion of FIG. 3,

[0019]FIG. 5, a cross section similar to the one in FIG. 3 in the unlatched position of rest of the arm,

[0020]FIG. 6, an enlarged detail from FIG. 5.

[0021] An embroidery unit 10 is represented in FIG. 1 as an example of a drive mechanism, which can be attached to the housing of a sewing machine with the aid of a plug connector 12. The embroidery unit 10 essentially consists of a support 14 with a mechanically displaceable support carriage 16, on which an arm 19 is fixed via a joint 18, said arm 19 having an arm carriage 20 which, in the operating position shown in FIG. 1, can be displaced perpendicularly in respect to the track of the support carriage 16. The arm carriage 20 has a holder 22, to which an embroidery frame as the holder for the material to be sewn can be attached, in which the material which is to be provided with the embroidery pattern can be clamped.

[0022] One advantage of the shown embroidery unit 10 is that with the aid of the joint 18 the arm 19 can be pivoted down into a position of rest, represented in FIG. 2, in which it extends essentially parallel with the support 14, so that in this position of rest or transport position the embroidery unit 10 can be stored in a space-saving manner in small and cost-efficient containers. Here, the arm 19 is interlockingly latched with the aid of teeth 24 in the operating position shown in FIG. 1, as well as in the position of rest shown in FIG. 2.

[0023] The structural design of the pivot mechanism with the joint 18 and the teeth 24 can be seen in greater detail in FIGS. 3 to 6.

[0024] The support carriage 16, which can be moved with the aid of an electric drive motor (not shown) and a toothed belt along a track parallel with the support 14, constitutes a first joint half of the joint 18 and has a bearing bushing 28, in which a pivot pin 30 is seated, which has been molded in a rail support 32 constituting the second joint half of the joint 18 and supports the arm 19. An electric drive motor 34 has also been attached directly to the rail support 32 and displaces the arm carriage 20 along its track. The control of the electric motors here is provided with the aid of the electronic control device of the sewing machine, wherein the connection is made with the aid of an electrical plug connector 35 (see FIGS. 1 and 2) when plugged into the plug connector 12.

[0025] In order to make possible the interlocked latching of the rail support 32 and the support carriage 16 in the operating position and the position of rest, the rail support 32 has conically designed toothed protrusions 36, which can be interlockingly latched in the direction of rotation into correspondingly designed grooves 38 in the front face of the support carriage 16 facing it. The protrusions 36 together with the grooves form said teeth 24. Releasing capability of the joint is provided by the divided bearing bush 28, wherein the upper bushing part 40 is pressed into the support carriage 16, and the second bushing part 42 is supported on a lock washer 46 on the pivot pin 30 against the force of a helical spring 44 supported on the support carriage 16. In this case play is provided between the two bushing halves 40, 42 in the latched position.

[0026] For pivoting the arm 19, the latter can be grasped in the area of a rib 48 and pulled upward against the force of the helical spring 44, until the front faces of the two bushing parts 40, 42 rest against each other (see FIGS. 5 and 6). In the process, the toothed protrusions 36 are disengaged from the grooves 38, so that thereafter the arm can be pivoted. In the area of its end positions, which are limited by stops (not shown), the helical spring 44 again pushes the conical toothed projections 36 into the grooves 38, so that an arrestment free of play of the arm 19 results.

[0027] The limitation of the lifting distance of the two bushing halves 40, 42 relative to each other prevents the collision of the mechanical elements of the arm with the housing of the support 14.

[0028] Other joint shapes are of course also conceivable which, for example, could make use of separate securing elements or clamping mechanisms, wherein with these embodiments raising of the arm 19 for disengaging the joint is not necessary.

[0029] Further variations of the represented exemplary embodiment may relate to the arrangement of the electrical drive motors and the gears for driving the carriages 16, 20. For example, both motors can be arranged in the support, wherein the power transfer to the arm carriage can take place via a drive wheel rotating around the pivot shaft, for example. Threaded spindle drives are also conceivable for both carriages.

[0030] The described embroidery unit can be delivered with an appropriately provided plug connector as an accessory for sewing machines, or it can be a component of a sewing machine, wherein it is usefully removable in order to make it possible to perform other sewing operations on the sewing machine. 

1. A drive mechanism with a holder (22) for material to be sewn for sewing machines, for example an embroidery unit (10) with an embroidery frame, which is attached to an arm carriage (20) which is moveable along a first track of an arm (19), wherein the arm (19) is attached to a support carriage (16), which for its part is moveable on a support (14) along a second track extending perpendicularly to the first track in an operating position, characterized in that the arm (19) is pivotable around a joint (18) from the operating position into a position of rest, in which the two tracks are essentially located parallel to each other.
 2. The drive mechanism in accordance with claim 1, characterized in that respectively one stop limits the pivot range of the arm (19) in the position of rest and in the operating position.
 3. The drive mechanism in accordance with claim 2, characterized in that the arm (19) is arranged to be positively locked at least in its operating position.
 4. The drive mechanism in accordance with claim 3, characterized in that interlocked latching elements (36, 38) which are preferably provided directly or indirectly on the arm (19) and/or the support carriage (16), are arranged to be disengaged against the force of a spring element (44).
 5. The drive mechanism in accordance with claim 4, characterized in that the arm (19) is axially displaceable on its pivot shaft against the force of a spring element (44) into a position, preferably limited by a stop (40, 42), in which the positive locking is interrupted.
 6. The drive mechanism in accordance with claim 5, characterized in that a first axial front face is provided on the arm (19), and a second axial front face on the support (14), wherein the front faces have corresponding, preferably conically designed groove elements (38) and protrusion elements (36) as the latching elements, which are disengaged in a position of the arm (19) raised against the spring element (44).
 7. The drive mechanism in accordance with claim 5 or 6, characterized in that the joint (18) has a divided bearing bushing (40, 42) wherein, for forming the stop, the bearing bushing preferably consists of two halves (40, 42), each with an annular face, which rest against each other in the maximally raised arm position.
 8. The drive mechanism in accordance with claim 1, characterized in that respectively one electric drive motor (34) is provided for the carriages (16, 20).
 9. The drive mechanism in accordance with claim 8, characterized in that at least one of the motors acts via a toothed belt drive on the corresponding carriage.
 10. The drive mechanism in accordance with claim 8, characterized in that the motor of the arm carriage (20) and the motor of the support carriage (16) are arranged in the support.
 11. A sewing machine, characterized by a drive mechanism in accordance with one of the preceding claims.
 12. The sewing machine in accordance with claim 10, characterized in that the drive mechanism is removable from the sewing machine housing or sewing machine body, respectively. 